1. Field of the Invention
The invention relates to a ground terminal that can be detached easily from the body of an automotive vehicle or the like at the time of dismantling, and to a method of forming such ground terminal.
2. Description of the Related Art
Ground wires are connected with the wire-connecting portions of ground terminals and the ground terminals are connected to bolts on the body of a vehicle. In recent years, there has been a demand for recycling parts of dismantled automotive vehicles. Accordingly, nonmetallic parts, such as wiring harnesses, are removed from metallic vehicle bodies. However, the ground terminals that are part of the wiring harnesses are fixed firmly to the vehicle body by the bolts, and they can be removed only by a labor-intensive operation, such as loosening the bolts.
Japanese Unexamined Patent Publication No. 9-92360 and FIG. 7 herein disclose a ground terminal that enables the wire and adjacent parts of a ground terminal to be removed from a vehicle body without loosening the bolt. In particular, a ground terminal 1 of FIG. 7 has a fixing portion 2 for fixing the ground terminal 1 to a vehicle body. The ground terminal 1 also has a wire-connecting portion 3 for connection to a wire and a coupling portion 4 between the fixing portion 2 and the wire-connecting portion 3. A groove 5 extends straight across the coupling portion 4 in the widthwise direction and defines a thin region of the coupling portion 4. The wire-connecting portion 3 can be gripped and bent repeatedly up and down to fracture the ground terminal 1 along the groove 5. As a result, the wire, the fixing portion 2 and adjacent parts of the coupling portion 4 can be separated from the fixing portion 2.
The ground terminal 1 is fractured due to metallic fatigue caused by bending along the groove 5. However, a strenuous bending operation is required to fracture the ground terminal 1. The groove 5 could be deepened to make the thinned portion even thinner and to facilitate the fracture of the ground terminal 1. However, the ground terminal 1 also becomes weaker against a pulling force along the longitudinal direction of the wire and there is a danger of inadvertent fracture. Further, a deep groove 5 defines a small a cross-sectional area and may exhibit insufficient electrical conductivity.
The invention was developed in view of the above, and an object thereof is to make a ground terminal separable at a coupling portion by light bending without reducing a sectional area of a portion to be fractured.
The invention relates to a ground terminal with a fixing portion formed with a bolt hole for receiving a bolt and/or a threaded shaft for fixing the ground terminal to a mount member. The ground terminal further includes a wire-connecting portion for connection to a wire and a coupling portion that joins the fixing portion and the wire-connecting portion. The coupling portion is thinned across substantially its entire width to form a fracture groove. The fracture groove is pointed, arrow-shaped or arch-shaped, and preferably has an apex substantially at the widthwise center of the coupling portion.
The fracture groove may be continuous or discontinuous, and may have a constant width or a varying width. Further, the pointed shape of the fracture groove may be a V-shape with a sharply pointed apex or a moderate curved parabolic shape. The fracture groove may take any shape, but preferably has the apex substantially in the center of the coupling portion. It does not matter whether the pointed tip faces toward the fixing portion or toward the wire-connecting portion.
The wire-connecting portion may be lifted up and bent with respect to the fixing portion that is bolted to the mount member of an automotive vehicle or the like. Thus, a fracture area gradually spreads along the fracture groove from the pointed apex, as a fracture starting point, to the opposite widthwise ends of the coupling portion. Thus, the ground terminal can be fractured and separated along the fracture groove substantially by one bending operation, and the fixing portion and part of the coupling portion are left behind. An operation force for the fracture can be reduced and a sectional area of the fracture groove can be set larger as compared to conventional straight fracture grooves. Thus, the ground terminal has sufficient strength against a pulling force on the wire. Further, the sectional area of the fracture groove can be enlarged, and the electrical conductivity of the ground terminal can be improved as compared to the straight fracture grooves.
The fracture groove preferably is formed in the surface of the coupling portion that faces the mount member. Thus, a lifting force on the wire-connecting portion widens the fracture groove, and the fracture proceeds easily along the fracture groove.
A projection preferably projects from a surface of the coupling portion opposite the fracture groove. The projection preferably is at a location substantially nested with the concave side of the apex of the fracture groove. The projection performs a reinforcing function and concentrates stress at the apex of the fracture groove, as a fracture starting point. Thus, the fracture can be started more easily when the wire-connecting portion is lifted to bend the ground terminal.
A bore may be formed at the apex of the fracture groove. The bore enables the fracture to be started more smoothly from the apex of the fracture groove.
The invention also relates to a method for forming a ground terminal. The method comprises stamping or cutting out a conductive plate to provide a fixing portion formed with a bolt opening for receiving a bolt and/or threaded shaft for fixing the fixing portion to a mount member. The method further comprises forming a wire-connecting portion for fixing a wire, and forming a coupling portion for coupling the fixing portion and the wire-connecting portion. The step of forming the coupling portion comprises forming a fracture groove by thinning the coupling portion over substantially the entire width thereof. The fracture groove is formed to have a pointed, arrow or arch-shape and may have an apex substantially toward the widthwise center of the coupling portion. Additionally, the fracture groove may be formed in a surface of the coupling portion that will face the mount member.
The method may further comprise the step of forming a projection on the coupling portion at a position proximate to the concave side of the apex of the fracture groove. Additionally, the projection is formed on a surface opposite from the one where the fracture groove is formed.
The method further may comprise the step of forming a bore at or near the apex of the fracture groove.
These and other objects, features and advantages of the invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are described separately, single features thereof may be combined to additional embodiments.